Ubuntu Security Notice 2846-1 - Felix Wilhelm discovered a race condition in the Xen paravirtualized drivers which can cause double fetch vulnerabilities. An attacker in the paravirtualized guest could exploit this flaw to cause a denial of service (crash the host) or potentially execute arbitrary code on the host. Konrad Rzeszutek Wilk discovered the Xen PCI backend driver does not perform sanity checks on the device's state. An attacker could exploit this flaw to cause a denial of service (NULL dereference) on the host. Various other issues were also addressed.
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Ubuntu Security Notice USN-2846-1
December 19, 2015
linux vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 12.04 LTS
Summary:
Several security issues were fixed in the kernel.
Software Description:
- linux: Linux kernel
Details:
Felix Wilhelm discovered a race condition in the Xen paravirtualized
drivers which can cause double fetch vulnerabilities. An attacker in the
paravirtualized guest could exploit this flaw to cause a denial of service
(crash the host) or potentially execute arbitrary code on the host.
(CVE-2015-8550)
Konrad Rzeszutek Wilk discovered the Xen PCI backend driver does not
perform sanity checks on the device's state. An attacker could exploit this
flaw to cause a denial of service (NULL dereference) on the host.
(CVE-2015-8551)
Konrad Rzeszutek Wilk discovered the Xen PCI backend driver does not
perform sanity checks on the device's state. An attacker could exploit this
flaw to cause a denial of service by flooding the logging system with
WARN() messages causing the initial domain to exhaust disk space.
(CVE-2015-8552)
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 12.04 LTS:
linux-image-3.2.0-97-generic 3.2.0-97.137
linux-image-3.2.0-97-generic-pae 3.2.0-97.137
linux-image-3.2.0-97-highbank 3.2.0-97.137
linux-image-3.2.0-97-omap 3.2.0-97.137
linux-image-3.2.0-97-powerpc-smp 3.2.0-97.137
linux-image-3.2.0-97-powerpc64-smp 3.2.0-97.137
linux-image-3.2.0-97-virtual 3.2.0-97.137
After a standard system update you need to reboot your computer to make
all the necessary changes.
ATTENTION: Due to an unavoidable ABI change the kernel updates have
been given a new version number, which requires you to recompile and
reinstall all third party kernel modules you might have installed.
Unless you manually uninstalled the standard kernel metapackages
(e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual,
linux-powerpc), a standard system upgrade will automatically perform
this as well.
References:
https://www.ubuntu.com/usn/usn-2846-1
CVE-2015-8550, CVE-2015-8551, CVE-2015-8552
Package Information:
https://launchpad.net/ubuntu/+source/linux/3.2.0-97.137